Quasicrystals

Quasicrystals. Crystals are surely the oldest known of the broken-symmetry phases of matter, and remain the most beautiful illustrations. It's amazing that in the past few years, we've uncovered an entirely new class of crystals. Shown here is a photograph of a quasicrystalline metallic alloy, with icosahedral symmetry. Notice the five-pointed stars: our old notions of crystals had to be completely revised to include this type of symmetry.